C＃：HttpClient，上传多个文件为MultipartFormDataContent时的文件上传进度 [英] C#: HttpClient, File upload progress when uploading multiple file as MultipartFormDataContent
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问题描述
我使用这段代码上传了多个文件，效果很好。它使用modernhttpclient库。
public async Task< string> PostImages（int platform，string url，List< byte []> imageList）
{
try {
int count = 1;
var requestContent = new MultipartFormDataContent（）;
foreach（var imageList in imageList）{
var imageContent = new ByteArrayContent（image）;
imageContent.Headers.ContentType = MediaTypeHeaderValue.Parse（image / jpeg）;
requestContent.Add（imageContent，image+ count，image.jpg）;
count ++;
}
var cookieHandler = new NativeCookieHandler（）;
var messageHandler = new NativeMessageHandler（false，false，cookieHandler）;
cookieHandler.SetCookies（cookies）;
using（var client = new HttpClient（messageHandler））{
client.DefaultRequestHeaders.TryAddWithoutValidation（User-Agent，GetUserAgent（platform））;
using（var r = await client.PostAsync（url，requestContent））{
string result = await r.Content.ReadAsStringAsync（）;
System.Diagnostics.Debug.WriteLine（PostAsync：+ result）;
返回结果;
$ b $ catch（Exception e）{
System.Diagnostics.Debug.WriteLine（e.Message）;
返回null;
$ / code $ / pre
现在我需要上传文件时的进度。我在谷歌搜索，发现我需要使用ProgressStreamContent
https://github.com/paulcbetts/ModernHttpClient/issues/80
由于ProgressStreamContent包含一个构造函数，它接受一个流，我转换MultipartFormDataContent将在其构造函数中进行流式处理和使用。但是，它不工作。上传失败。我认为它是因为它是所有文件的流，这是不是我的后端预期。
公共异步任务< ;串GT; PostImages（int platform，string url，List< byte []> imageList）
{
try {
int count = 1;
var requestContent = new MultipartFormDataContent（）;
//这里你可以指定边界如果你需要--- ^
foreach（var imageList in imageList）{
var imageContent = new ByteArrayContent（image）;
imageContent.Headers.ContentType = MediaTypeHeaderValue.Parse（image / jpeg）;
requestContent.Add（imageContent，image+ count，image.jpg）;
count ++;
}
var cookieHandler = new NativeCookieHandler（）;
var messageHandler = new NativeMessageHandler（false，false，cookieHandler）;
cookieHandler.SetCookies（RestApiPaths.cookies）;
var stream = await requestContent.ReadAsStreamAsync（）;
var client = new HttpClient（messageHandler）;
client.DefaultRequestHeaders.TryAddWithoutValidation（User-Agent，RestApiPaths.GetUserAgent（platform））;
var request = new HttpRequestMessage（HttpMethod.Post，url）;
var progressContent = new ProgressStreamContent（stream，4096）;
progressContent.Progress =（bytes，totalBytes，totalBytesExpected）=> {
Console.WriteLine（上传{0} / {1}，totalBytes，totalBytesExpected）;
};
request.Content = progressContent;
var response = await client.SendAsync（request）;
string result = await response.Content.ReadAsStringAsync（）;
System.Diagnostics.Debug.WriteLine（PostAsync：+ result）;
返回结果;
catch（Exception e）{
System.Diagnostics.Debug.WriteLine（e.Message）;
返回null;
$ b $ p
$ b我应该在这里做些什么来得到这个工作？任何帮助表示赞赏解决方案我有一个ProgressableStreamContent的工作版本。请注意，我在构造函数中添加了头文件，这是原始ProgressStreamContent中的一个错误，它不会添加头文件！
内部类ProgressableStreamContent：HttpContent
{
///< summary>
///让我们保留20kb的缓冲
///< / summary>
private const int defaultBufferSize = 5 * 4096;
私人HttpContent内容;
private int bufferSize;
//私人bool contentConsumed;
private action< long，long>进展;
$ b $ public ProgressableStreamContent（HttpContent content，Action< long，long> progress）：this（content，defaultBufferSize，progress）{}
$ b $ public ProgressableStreamContent（HttpContent content，int bufferSize， （内容== null）
{
throw new ArgumentNullException（content）;
if（bufferSize< = 0）
{
throw new ArgumentOutOfRangeException（bufferSize）;
}
this.content = content;
this.bufferSize = bufferSize;
this.progress =进度;
foreach（content.Headers中的var h）{
this.Headers.Add（h.Key，h.Value）;
$ b保护覆盖任务SerializeToStreamAsync（Stream stream，TransportContext上下文）
{
return Task.Run（async（） =>
{
var buffer = new Byte [this.bufferSize];
long size;
TryComputeLength（out size）;
var uploaded = 0;
使用（var sinput = await content.ReadAsStreamAsync（））
（
while（true）
{
var length = sinput。读取（缓冲区，0，buffer.Length）;
if（length <= 0）break;
//downloader.Uploaded =上传+ =长度;
已上传+ =长度;
进度？.Invoke（上传，大小）;
//System.Diagnostics.Debug.WriteLine($Bytes sent {uploaded} of {size}）;
stream.Write（buffer，0，le NGTH）;
stream.Flush（）;
}
}
stream.Flush（）;
}）;
protected override bool TryComputeLength（out long length）
{
length = content.Headers.ContentLength.GetValueOrDefault（）;
返回true; （bool处置）
{
如果（处理）
{
content.Dispose（）;
保护覆盖无效处置
}
base.Dispose（disposing）;
$ p
$ b 还要注意，它期望HttpContent，
$ p $ var progressContent = new ProgressableStreamContent（
requestContent，
4096，
（sent，total）=> {
Console.WriteLine（上传{0} / {1}，发送，总计）;
}）;
I'm using this code to upload multiple files and it working very well. It uses modernhttpclient library.
public async Task<string> PostImages (int platform, string url, List<byte []> imageList)
{
try {
int count = 1;
var requestContent = new MultipartFormDataContent ();
foreach (var image in imageList) {
var imageContent = new ByteArrayContent (image);
imageContent.Headers.ContentType = MediaTypeHeaderValue.Parse ("image/jpeg");
requestContent.Add (imageContent, "image" + count, "image.jpg");
count++;
}
var cookieHandler = new NativeCookieHandler ();
var messageHandler = new NativeMessageHandler (false, false, cookieHandler);
cookieHandler.SetCookies (cookies);
using (var client = new HttpClient (messageHandler)) {
client.DefaultRequestHeaders.TryAddWithoutValidation ("User-Agent", GetUserAgent (platform));
using (var r = await client.PostAsync (url, requestContent)) {
string result = await r.Content.ReadAsStringAsync ();
System.Diagnostics.Debug.WriteLine ("PostAsync: " + result);
return result;
}
}
} catch (Exception e) {
System.Diagnostics.Debug.WriteLine (e.Message);
return null;
}
}
Now I need the progress when uploading the files. I searched in google and found I need to use ProgressStreamContent
https://github.com/paulcbetts/ModernHttpClient/issues/80
Since ProgressStreamContent contains a constructor that takes a stream, I converted the MultipartFormDataContent to stream and used it in its constructor. But, its not working. Upload fails. I think its because it is a stream of all the files together which is not what my back end is expecting.
public async Task<string> PostImages (int platform, string url, List<byte []> imageList)
{
try {
int count = 1;
var requestContent = new MultipartFormDataContent ();
// here you can specify boundary if you need---^
foreach (var image in imageList) {
var imageContent = new ByteArrayContent (image);
imageContent.Headers.ContentType = MediaTypeHeaderValue.Parse ("image/jpeg");
requestContent.Add (imageContent, "image" + count, "image.jpg");
count++;
}
var cookieHandler = new NativeCookieHandler ();
var messageHandler = new NativeMessageHandler (false, false, cookieHandler);
cookieHandler.SetCookies (RestApiPaths.cookies);
var stream = await requestContent.ReadAsStreamAsync ();
var client = new HttpClient (messageHandler);
client.DefaultRequestHeaders.TryAddWithoutValidation ("User-Agent", RestApiPaths.GetUserAgent (platform));
var request = new HttpRequestMessage (HttpMethod.Post, url);
var progressContent = new ProgressStreamContent (stream, 4096);
progressContent.Progress = (bytes, totalBytes, totalBytesExpected) => {
Console.WriteLine ("Uploading {0}/{1}", totalBytes, totalBytesExpected);
};
request.Content = progressContent;
var response = await client.SendAsync (request);
string result = await response.Content.ReadAsStringAsync ();
System.Diagnostics.Debug.WriteLine ("PostAsync: " + result);
return result;
} catch (Exception e) {
System.Diagnostics.Debug.WriteLine (e.Message);
return null;
}
}
What should I do here to get this working? Any help is appreciated
解决方案 I have a working version of ProgressableStreamContent. Please note, I am adding headers in the constructor, this is a bug in original ProgressStreamContent that it does not add headers !!
internal class ProgressableStreamContent : HttpContent
{
/// <summary>
/// Lets keep buffer of 20kb
/// </summary>
private const int defaultBufferSize = 5*4096;
private HttpContent content;
private int bufferSize;
//private bool contentConsumed;
private Action<long,long> progress;
public ProgressableStreamContent(HttpContent content, Action<long,long> progress) : this(content, defaultBufferSize, progress) { }
public ProgressableStreamContent(HttpContent content, int bufferSize, Action<long,long> progress)
{
if (content == null)
{
throw new ArgumentNullException("content");
}
if (bufferSize <= 0)
{
throw new ArgumentOutOfRangeException("bufferSize");
}
this.content = content;
this.bufferSize = bufferSize;
this.progress = progress;
foreach (var h in content.Headers) {
this.Headers.Add(h.Key,h.Value);
}
}
protected override Task SerializeToStreamAsync(Stream stream, TransportContext context)
{
return Task.Run(async () =>
{
var buffer = new Byte[this.bufferSize];
long size;
TryComputeLength(out size);
var uploaded = 0;
using (var sinput = await content.ReadAsStreamAsync())
{
while (true)
{
var length = sinput.Read(buffer, 0, buffer.Length);
if (length <= 0) break;
//downloader.Uploaded = uploaded += length;
uploaded += length;
progress?.Invoke(uploaded, size);
//System.Diagnostics.Debug.WriteLine($"Bytes sent {uploaded} of {size}");
stream.Write(buffer, 0, length);
stream.Flush();
}
}
stream.Flush();
});
}
protected override bool TryComputeLength(out long length)
{
length = content.Headers.ContentLength.GetValueOrDefault();
return true;
}
protected override void Dispose(bool disposing)
{
if (disposing)
{
content.Dispose();
}
base.Dispose(disposing);
}
}
Also note, it expects HttpContent, not stream.
This is how you can use it.
var progressContent = new ProgressableStreamContent (
requestContent,
4096,
(sent,total) => {
Console.WriteLine ("Uploading {0}/{1}", sent, total);
});
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